The present invention relates to a semiconductor device and a design support method of an electronic device having the semiconductor device assembled on a substrate or printed circuit board.
At present, data sheets or sales catalog for showing the performance of semiconductor devices, such as microprocessors and LSIs (e.g., ASICs), describe the electric characteristics of the LSIs: (1) absolute rating (FIG. 14); (2) DC characteristics (FIG. 15); and (3) AC characteristics (FIG. 16). In addition, the timing accuracy and delay time for clock and control and bus signals of each of signal terminals are provided to describe the AC characteristics(FIG. 17).
However, the description of EMI (Electro Magnetic Interference) in a substrate packaged with the LSI and in a device mounted with the substrate is not generally provided. The description on power supply noise intensity of the power supply terminals and GND terminals of an LSI also is not generally provided. These electrical characteristics have a significant effect on operating accuracy of the substrate and the device. Similarly, the description on countermeasures to noises for the terminals and priority of the countermeasures are not described in the data sheets or product catalogs.
Japanese Patent Laid-Open No. 7063/1995 discloses a highly accurate verification method in which a signal pad subject to noises is identified according to logic circuit data and cell attributes in power/GND pads and signal pads of an LSI and a mutual noise figure is sought between the signal pad and the power/GND pads to determine whether a power/GND pad generating noises exists near the signal pad subject to noises, as shown in FIG. 18. Japanese Patent Laid-Open No. 174087/2000 discloses a noise analyzer capable of taking efficient countermeasures to power supply noises in which a power system net list of an LSI chip is extracted and power system noise current is simulated to show the power system net list and the simulation results, as shown in FIG. 19.
However, for users installing an LSI on a substrate, it has been difficult to obtain power supply noise intensity information and noise level classification information about all the power supply and GND terminals in the LSI even if the verification method or analyzer is used.
On this account, the users have installed countermeasure components, such as a bypass condenser or EMI filter, for every power supply and GND terminal of the LSI, in order to reduce the electromagnetic interference in the substrate or device, or to stabilize operations of the substrate or the device. Alternatively, the users themselves have tested the noise intensity of every power supply and GND terminal of a semiconductor device, identified the power supply and GND terminals with a high noise intensity, and then installed the countermeasure components.